Aaron looking at the aspects of the XBRR, bottom end, bore/stroke ratio, porkchop flywheels, the heavy finning ect..... Would you consider this the pinacle of aircooled twin cylinder race engines? I know it had a short race career, racing against water cooled four valve twins was nigh on impossible I guess ??? If you could would you have designed it any differently ???

Oh, I don't know, as soon as you say something is the "pinnacle" somebody will come up with something better. I'd say it's very well done, but pinnacle is too strong of a word.

What I see is a lot of redesign with the application of a bunch of things that are already well known, like over square bore & stroke, light flywheels, and straight ports. There's nothing really revolutionary here, but for performance, it's definitely light years ahead of the XL mill. They fixed the exact things that hold the XL motor back. They also didn't cut cost the way they do on the production bikes, everything is done right.

What really amazes me about the thing is how much redesign and retooling they had to do. I mean, these motors have very few XL or XB parts in them. It takes a lot of time and effort to develop this many new parts ... new castings, new CNC processes, new fixtures, etc. They poured a bunch of time and money into this thing considering there was a production run of a whopping 56 bikes. They must've spent a fortune, I guarantee you they lost money selling the bikes at $31K a pop. Absolutely amazing to me that they'd do that.

No, they're special rockers but they don't have roller tips. I'll post some pics of the assembled top end when I get a chance and show them. The whole valvetrain geometry is quite a bit different from the XL or XB mill.

Based on what I have read, the firebolt was originally desinged as a 900 turbo and a short stroke 1350 with natural aspiration. I think the basic design, with cheaper materials, almost made it to production.

Oh, I don't know, as soon as you say something is the "pinnacle" somebody will come up with something better. I'd say it's very well done, but pinnacle is too strong of a word.

What I see is a lot of redesign with the application of a bunch of things that are already well known, like over square bore & stroke, light flywheels, and straight ports. There's nothing really revolutionary here, but for performance, it's definitely light years ahead of the XL mill. They fixed the exact things that hold the XL motor back. They also didn't cut cost the way they do on the production bikes, everything is done right.

What really amazes me about the thing is how much redesign and retooling they had to do. I mean, these motors have very few XL or XB parts in them. It takes a lot of time and effort to develop this many new parts ... new castings, new CNC processes, new fixtures, etc. They poured a bunch of time and money into this thing considering there was a production run of a whopping 56 bikes. They must've spent a fortune, I guarantee you they lost money selling the bikes at $31K a pop. Absolutely amazing to me that they'd do that.

So what happened to all the new castings, processes, and fixtures? Where did the 'intelligent design' go? I wonder if this was simply a prelude or possibly a testing process. Maybe the long-term plan is awaiting just over the horizon?

So what happened to all the new castings, processes, and fixtures? Where did the 'intelligent design' go? I wonder if this was simply a prelude or possibly a testing process. Maybe the long-term plan is awaiting just over the horizon?

What's really odd is they were doing all this as they were simultaneously developing the 1125, watercooled DOHC 4-valve. So they knew this thing was going to be short-lived, and enormously expensive, and yet they did it anyway.

Someday I'd like to hear the real story of how this came about. I just can't imagine how they justified it.

Considering the company is gone now, I wouldn't look for anything over the horizon.

What's really odd is they were doing all this as they were simultaneously developing the 1125, watercooled DOHC 4-valve. So they knew this thing was going to be short-lived, and enormously expensive, and yet they did it anyway.

Someday I'd like to hear the real story of how this came about. I just can't imagine how they justified it.

Considering the company is gone now, I wouldn't look for anything over the horizon.

Agreed. From an organizational perspective, the return on investment would not justify the cost of capital unless there's more to the story. There must be more to the story. I don't believe any company could be so flippant with a plan.

Great pictures Aaron, and some interesting development ideas. It's a pity some of this technology couldn't have been transferred to road bikes and put the sport back into Sportster. Presumably, the MoCo still owns the rights to all this...

It is a unique story especially to HD, they usually get huge returns from race projects, ie KR and especially XR 750 hstory. Let's face it the VR 1000 never really panned out, maybe they didn't fund it properly, anyone's guess, but for so much "new" stuff to be in the XBRR and it only be raced for 2 years ?? that is strange. Then the 1125 comes along and all of a sudden Buell is dead. Too bad because a developmental oofshoot the 1190 has big numbers and can compete with other Race twins and win, just not on a world stage yet.....

I dont remember exactly but was there not some big problem/issue with Willie G and Eric B fighting about this engine/bike at and before it was raced. My impression is Willie G is really out of touch with todays sport bikes but yet still thinks he knows all about it?. I never did and dont care for old willie g sence of race?/perf? "styling" really at all.

Anyone know anything about this story?. It would be really nice to know more details on this.

Also thinking about it now didint they also fight about the vr1000 engine too???, my impression is they did not get along.